Scientists at the University of Copenhagen studied the immediate reaction of the body in response to quitting smoking and have unraveled a mechanism where they found decreased blood flow and oxygen uptake in the brain, just 12 hours after abstaining from smoking. This not only explains why it is so hard to kick off the habit but also why smoking should be quit gradually.
Smoking is harmful in almost every respect. There is no way around it. It is harmful for nearly every organ of the body. The health effects of smoking with respect to lung cancers and respiratory diseases are well known, however, its role in causing strokes, cardiovascular diseases and cancers of other parts of the body are just a small part of a well-documented portfolio of serious consequences of smoking.
According to official estimates, smoking is the most preventable cause of death globally. What makes smoking so addictive is the presence of chemical nicotine in cigarettes that is quickly absorbed into the bloodstream. Within 10 seconds of entering the body, nicotine reaches the brain and causes the brain to release a powerful hormone called adrenaline that creates a buzz of pleasure and energy. However, this buzz is short-lived and leaves you tired and wanting the buzz again. And before you know it, smoking becomes a habit to go with your coffee or conversations or stress, leading to addiction.
However, in contrast to the established conventions of giving up smoking suddenly, scientists have always argued that you should always practice a stepwise method of reducing nicotine intake before giving it up completely. In this latest study published in the Journal of Cerebral Blood Flow & Metabolism, Dr. Vafaee’s group compared the blood flow in brain and oxygen uptake in 12 habitual, heavy smokers to 12 non-smokers using Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI) at different time points after smoking and abstaining from smoking.
After smoking, brain activity increases initially because of the “adrenaline rush”. Interestingly, consistent with their hypothesis, these scientists found that abstention from smoking by habitual smokers lead to a substantial decline in blood perfusion in brain and oxygen metabolism. This decrease, according to brain scans that measured the brain’s oxygen uptake and blood flow is to the tune of 17% after 12 hours of abstinence. This is one of the primary reasons that smokers crave for a nicotine puff because the stimulant effect of nicotine and other components of tobacco cause a rapid reversal of this effect.
“Regular smokers experience an almost dementia-like condition in the early hours after quitting, as suggested by brain scans. This can be quite an unpleasant experience, and is probably one of the reasons why it can be very difficult to quit smoking once and for all. Smokers drift back into abuse, perhaps not to obtain a pleasant effect — that ship has sailed — but simply because the withdrawal symptoms are unbearable,” says Professor Albert Gjedde, neuroscience researcher at the Department of Neuroscience and Pharmacology, University of Copenhagen who has also contributed to the findings.
Even though the number of subjects in the experiment is small, the study is significant because it is the first of its kind in almost 40 years. Interestingly, similar studies have been carried out on rats and the mechanism explained but no past studies have linked blood flow and oxygen uptake in the brain to giving up smoking. However, the researchers still do not know how long it takes before the brain of a former smoker has regained its normal energy consumption and blood flow.
“We assume that it takes weeks or months, but we do not know for sure. The new findings suggest that it may be a good idea to stop smoking gradually — simply to avoid the worst withdrawal symptoms that make it so difficult to stick to the otherwise very sensible decision to stop smoking,” says Albert Gjedde. Inspite of the numerous blind spots, this is just a small but significant step in elucidation of the fascinating way in which human brain functions and responds.
The original paper can be accessed here.